Table 4-11 and Table 4-12 illustrate the boolean values returned for AND, OR, and NOT.

Table 4-11. The AND and OR Operators

a b a AND b a OR b
TRUE TRUE TRUE TRUE
TRUE FALSE FALSE TRUE
TRUE NULL NULL TRUE
FALSE FALSE FALSE FALSE
FALSE NULL FALSE NULL
NULL NULL NULL NULL

Table 4-12. The NOT Operator

a NOT a
TRUE FALSE
FALSE TRUE
NULL NULL